Inflammation & Repair Flashcards
What form of cell death causes an inflammatory response?
Necrosis
Three features of acute inflammation?
- Dilation & hyperaemia
- Oedema exudate
- Leukocyte…Neutropils recruitment & activation
five signs of acute inflammation
- Heat - hyperaemia
- redness - hyperaemia
- swelling - oedema due to hyperaemia & increased permeability
- pain - stretch receptors & chemical mediators
- loss of function - swelling & pain
three possible outcomes of acute inflammation?
- Resolution
- organization
- chronic inflammation
three main components of granulation tissue & their role/purpose in repair
- fibroblasts: secrete collagen proteins
- Macrophages: coordinate events & clean up debris
- Angiogenesis: the formation of new blood vessels to provide nutrients and blood gases during the repair process
Consequences of healing through organization
Scarring allows repair & fills in the tissue deficits so we can survive but it lacks the properties of the tissue that it replaces reducing function reserve.
What are the three main causes of chronic inflammation
- repeated acute inflammation
- unresolved acute when the stimulus causing the acute response remains
- special cases
three general features of chronic inflammation
- ongoing tissue injury and destruction
- lymphocytes
- repeated attempts at repair through the formulation of granulation tissue and , when occurring in stable/labile tissues, proliferation of parenchymal cells
possible negative consequences of chronic inflammation
A lot more tissue destruction and scarring, a lot more loss of functional of tissue. If there is epithelial tissue, there will be an increased risk of cancer
Non-Sterile sites in the body
should have microorganisms:
skin, GIT, upper respiratory, lower urogenital
Sterile sites in the body
shouldn’t have microorganisms:
blood, brain & CSF, bone & marrow, lower respiratory, upper urogenital
Innate Response:
- fast
- not specific
- germ-line encoded
- cellular: neutrophils, macrophages, NK cells
- Humoral: complement components
Acquired Response:
- slow
- able to differentiate between targets
- learns & remembers ‘memory’
- Cellular: T & B Cells
- Humoral: Antibodies
Autoimmune Response
Immune system targeting itself without a stimulus
Hypersensitivity Response
Overreaction to stimulus
when can acute inflammation be life-threatening?
The brain, lungs & throat, lungs, pericardium, pleura & peritoneum
What type of oedema is observed in acute inflammation and how does it occur?
Exudate, which is an oedematous fluid which is high in proteins. hyperaemia results in increased hydrostatic pressure which forces fluid from the vessels into the tissue (transudate) but there is also increased vascular permeability which allows plasma proteins to also enter the fluid hence why we get an exudate.
What factors may prevent complete repair from occurring?
Permanent tissues like the brain and heart will never heal by resolution as neurons. In labile/stable tissues resolution is not possible when a lot of tissue has been lost or when there is overlying infection, poor immunity, poor nutrition, or interruption of healing
Under what circumstances does granulation tissue occur?
Granulation tissue is the immature scar, the tissue that forms the scar and so will occur in acute inflammation that heals through organization, and it will always be present in chronic inflammation as part of the repeated attempts at repair
what happens to the heart in response to ischemia?
The heart tissue affected by ischemia would have survived using anaerobic metabolism for a short period of time before succumbing to necrosis. The infarcted tissue would stimulate the acute inflammatory response……
Transition from acute to chronic inflammation
If there is little pain perceived and function is unimpaired, acute inflammation within an internal organ may elicit no or only subtle clinical symptoms. Without overt symptoms alerting to the presence of pathology treatment may not be administered and an acute inflammatory response may become chronic. Chronic inflammation may also occur when the immune system fails to distinguish self from non-self and in response to some infections
In most of the specimens the process of chronic inflammation is ongoing because the cause persists. If the cause of the chronic inflammation had been treated, what would have happened?
The granulation tissue would have matured into scar tissue as happens with organization.
How can chronic inflammation lead to cancer?
increased proliferation of epithelial cells and oxidative stress because of chronic inflammation has led to the development of cancer. it is NOT the inflammatory cells ) that give rise to cancer but the surrounding epithelium.
following a myocardial infarction what type of inflammation and repair occurs?
inflammation = acute repair = organization
Why does chronic inflammation increase the risk of carcinoma formation?
When chronic inflammation occurs in stable or labile tissues that contain epithelial cells, surrounding epithelial cells will proliferate (undergo hyperplasia) in a futile attempt to repair. This increase in proliferation & the presence of free radicals increases the chance of mutation. Note that it is not the granulation tissue that causes cancer & repair does not necessarily involve cell division
what is the mature scar tissue made our ot (apart from in the brain)
collagen protein (in the brain it is glial)
